[bug] fix group header alignment

Author: zombieFox

src/css/group.css

@@ -26,13 +26,25 @@
 .group-header{
 position: relative;
 display: flex;
-flex-direction: row;
-justify-content: flex-start;
 align-items: center;
 flex-wrap: nowrap;
 transition: padding var(--layout-timing-extra-fast);
 }
 
+.is-group-area-alignment-left .group-header{
+flex-direction: row;
+}
+
+.is-group-area-alignment-center .group-header{
+flex-direction: row;
+justify-content: center;
+}
+
+.is-group-area-alignment-right .group-header{
+flex-direction: row-reverse;
+justify-content: flex-start;
+}
+
 .is-group-name-show .group-header,
 .is-link-edit .group-header{
 padding-bottom:calc(var(--layout-space) *var(--layout-gutter));
@@ -77,7 +89,6 @@
 }
 
 .is-link-edit .group-control{
-margin-right:1em;
 height:2.5em;
 width:16em;
 transition:
@@ -86,6 +97,15 @@
  margin var(--layout-timing-extra-fast) var(--layout-duration-04);
 }
 
+.is-group-area-alignment-left .group-control,
+.is-group-area-alignment-center .group-control{
+margin-right:1em;
+}
+
+.is-group-area-alignment-right .group-control{
+margin-left:1em;
+}
+
 .group-control-item{
 width:4em;
 flex-shrink:0;